While I have detailed why it’s not a good idea to power level early on, here is how you power level within Onigiri. Remember to make sure Lady Shizuka and Susanoo are leveled with their respective friendship items. Lady Shizuka needs to be level 10 before leaving Sekigahara otherwise you cannot proceed. Susanoo needs to be around level 15 before hitting the end game area.
You will get 70 friendship items for Susanoo just before his quest where he needs to be level 15 which does boost his levels quite a bit.
Now, the power leveling. In terms of how fast this is, it really isn’t. But nothing matches the raw experience dropped when your party gets the killing blow with the 200% experience bonus boost. If your party doesn’t get the last hit then you get no experience. So watch and judge to make sure you don’t waste the boost. Of course, without the boost you still get a decent chunk of experience!
Each area has a world boss that is higher in level and much more powerful then the other enemies on the field. You want to fight the bosses that are higher level than you otherwise you get no experience. You get money and friendship items but no experience.
If you can, get into a team. Not only is this beneficial if one is a healer, but that you will all share in the bounty if one of them nets the killing blow. Many higher level players will often help lower players during a world boss fight and will hold off when the boss is almost dead.
Each area that you visit in order is how you should go about fighting the bosses. Most of the time you can drag them over to a more favorable location on the map with less enemies, or in Sekigahara and Nether Sekigahara, you can force the boss to one of the platforms and get him stuck on the edge.
If you’re lucky enough to get the kill, you will jump in level. The lower level you are to the boss, the higher you will jump but it isn’t recommended being too low since you won’t deal as much damage and die a lot more easier.
Generally it takes about an hour to kill a boss, depending on the players levels that are fighting. Naturally, this means you will start losing durability on your weapons. It is safe to go back to town and repair! And highly recommended. Also, in the event of death, do not use soul eggs. Simply click give up to respawn in the town and go back.
If you plan on using an experience booster, wait until the bosses health has a sliver of green and then use it.
Got the last hit? Now watch those levels soar!